Paperboard carton having an audible locking sound

ABSTRACT

An improved recloseable paperboard package for containing a granular material, includes a container base and a lid formed from a single piece of paperboard. The container base includes a first panel which forms a locking mechanism with the lid. When the lid is closed, an audible locking sound is heard having a sound pressure level of at least about 78 dB SPL .

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/376,388 (P&G Case AA-590FP), filed Apr. 29, 2002.

FIELD OF THE INVENTION

[0002] The present invention relates to paperboard cartons.Specifically, the present invention relates to paperboard cartons forcontaining granular materials.

BACKGROUND OF THE INVENTION

[0003] Reclosable cartonboard cartons for storing granular materials,such as powdered laundry detergents, have been available for many years.These cartons are typically formed from a cardboard which is laminatedor coated with a moisture barrier material, such as polyethylene,polypropylene, varnish or other barrier materials known in the art.Because the cardboard has a natural spring back, the lids of thesecartons tend to open thereby leading to contamination of the productand/or absorption of moisture by the product, both of which areundesirable. As such, the ability to repeatedly open and close/lockthese cartons has long been a desirable property.

[0004] Some closure/locking systems have included various flap and tabinterlocking arrangements in combination with a perforated line. In sucha carton, the perforation between the locking flap and the tab is brokenby a user during the peak first opening. These closure arrangementsgenerally require highly accurate folding and gluing steps duringmanufacture to achieve proper alignment between the locking flap and thetab, but when the perforation is too hard to break, it may be toodifficult to open the lid.

[0005] In addition, it has now been found that consumers aredissatisfied by current locking systems for the lid of a paperboardcarton, as they are viewed as less secure than, for example, a plasticlid. However, employing a plastic lid adds significant raw materialcosts to the carton, as well as manufacturing and supplier complexitiesand expenses. While paperboard cartons may also employ separatepaperboard lids which are glued to the main carton after the detergentis filled therein, such a separate manufacturing step and cartonformation step also can significantly add expenses and complexity to amanufacturing line.

[0006] Accordingly, the need exists for a paperboard carton which isrepeatably openable and closable, which is easy to open the first timeand subsequent times, which has a lid which is securely closeable and/orwhich significantly reduces manufacturing complexity and/or expenses.

SUMMARY OF THE INVENTION

[0007] The present invention relates to an improved reclosablepaperboard package for containing a granular material, including acontainer base and a lid formed from a single piece of paperboard. Thecontainer base includes a first panel which forms a locking mechanismwith the lid. When the lid is closed, an audible locking sound is heardhaving a sound pressure level of at least about 78 dB_(SPL). Thereclosable paperboard package also preferably has a peak first openingstrength of less than 70 N.

[0008] It has now been found that a paperboard package may be repeatablyopenable and closeable and yet still provide a securely closeablepackage. Furthermore, it has now been found that such a package may bemade from a single piece of paperboard, thereby saving significantmanufacturing and raw material expenses and reducing manufacturingcomplexity.

[0009] All documents cited are, in relevant part, incorporated herein byreference; the citation of any document is not to be construed as anadmission that it is prior art with respect to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] While the specification concludes with claims particularlypointing out and distinctly claiming the invention, it is believed thatthe invention will be better understood from the following descriptionof the accompanying figures in which like reference numerals identifylike elements, and wherein:

[0011]FIG. 1 is a perspective view of a preferred embodiment of thereclosable paperboard package herein in the open position with the lidraised;

[0012]FIG. 2 is a perspective view of a preferred embodiment of thereclosable paperboard package herein, prior to opening;

[0013]FIG. 3 is a top plan view of a preferred blank suitable for makingthe reclosable paperboard package herein, with a close-up of a preferredopening tab;

[0014]FIG. 4 is an enlarged partial cross-sectional side view of thepackage of FIG. 2, taken along line 4-4 to show a preferred lockingmechanism;

[0015]FIG. 5 is an enlarged partial cross-sectional side view of apreferred embodiment of an alternate locking mechanism; and

[0016]FIG. 6 is a top plan view of a preferred blank suitable for makingthe reclosable paperboard package herein, with a close-up of a preferredopening tab.

[0017] The figures herein are not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE INVENTION

[0018] As used herein, the term “comprising” means that other elements,which do not affect the end result can be added. This term encompassesthe terms “consisting of” and “consisting essentially of”.

[0019] As used herein, the term “dB_(SPL)” indicates the sound pressurelevel (SPL), in decibels. SPL is a single measurement of sound pressurein decibels relative to the threshold of hearing. SPL measurements aredefined herein as 2×10⁻⁵ Newtons per Meter² or 20 microPascals.

[0020] Referring to the figures, in FIG. 1, a preferred reclosablepaperboard package, 10, is illustrated as a six-sided carton having acontainer base, 12, having a first panel, 14, a second panel, 16, andtwo side panels, 18. A lid, 20, is attached to the second panel, 16, bya folded hinge, 22. The folded hinge, and in fact, most corners, ispreferably formed by an integral score line in the paperboard blank(see, FIG. 3, at 36), although other means known in the art may be used,such as half-cuts. The lid, 20, contains two lid side panels, 24, and alid front panel, 26, which further contains three lock tabs, 28 a, whichcooperate with the three corresponding lock slot, 28 b, to form threelocking mechanisms, 28, distal to the folded hinge, 22. Each lock tab,28 a, preferably tapers toward its distal end, to facilitate engagementof the distal end with its corresponding lock slot, 28 b. While a singlelocking mechanism may be sufficient in the above design, multiple lockmechanisms are preferred, as the lid is more securely held in place, andalso because they increase the sound pressure level of the audiblelocking sound.

[0021] The side panel, 18, has a depth, α, which is less than the depth,β, of the lid side panel, 24. This difference in depth between α and βfacilitates the creation of an audible locking sound when the lid isclosed. For optimal sound generation, ease of use, and economy, thedifference (see FIG. 4 at A) in depth between α and β is typically fromabout 0.5 mm to about 15 mm, preferably from about 1 mm to about 10 mm,and more preferably from about 2 mm to about 5 mm. Without intending tobe limited by theory, it is believed that if this difference is toosmall, little audible locking sound is heard, whereas if this differenceis too large, excessive paperboard is used, thereby wasting rawmaterials, and increasing expenses.

[0022] The first panel, 14, second panel, 16, and two side panels, 18,further define an opening, 32, through which the product, 30, may beremoved from the package, 10, when the lid, 20, is in the raisedposition.

[0023]FIG. 2 shows a six-sided carton having a lid, 20, interconnectedwith a container base, 12, first panel, 14, second panel, 16, containerbottom, 34, and side panels 18. The lid, first panel, second panel andside panels each have inner and outer surfaces, wherein the innersurfaces are disposed within the interior of the package, 10, and theexterior surfaces are disposed about the exterior of the package (theexterior surfaces only being visible in FIG. 2). FIG. 2 also shows thelock tab, 28, engaged within the lock slot, 28 b, to form the lockingmechanism, 28. The locking mechanism, 28, keeps the lid, 20, closed toprevent spillage of the granular material, moisture absorption by thegranular material, contamination of the granular material, etc.

[0024] In FIG. 3, a top plan view of a preferred blank, 36, suitable formaking the reclosable paperboard package herein with a close up of apreferred opening tab, 37, is provided, specifically showing the locktabs, 28 a. The blank, 36, also indicates that the depth, β, of the lid,20, is greater than the depth, α, of the side panel, 18. Similarly, thewidth, δ of the lid, 20, is greater than the width, γ, of the secondpanel, 16, and the first panel, 14. This, in turn, increases the soundpressure level of the locking mechanism, 28, when the lid, 20, isclosed. The opening tab, 37, further facilitates the first opening ofthe package, 10, as it provides a breaking seal which has a relativelylow peak first opening strength. The opening tab, 37, is typicallyaffixed to the inside of the lid, 20, at a suitable location to insure aseal. The blank, 36 of FIG. 3 is viewed from the side which becomes theoutside of the final reclosable paperboard package.

[0025]FIG. 3 also indicates a plurality of half-cuts, 38, which allowthe peak first opening strength to be significantly decreased. In thefigures, half-cut lines are indicated by dashed and dotted lines.Additional half-cuts, 38 a, are also indicated on the backside of theblank, 36. the lock tab, 28 a, also is defined with a half-cut, 38,which significantly increases the flexibility of the lock tab, 28 a, andvolume of the audible locking sound, as compared to a mere fold. As usedherein, the term “peak first opening strength” indicates the maximum orpeak amount of force required to open the package, 10, the first timeafter sealing, by lifting the lid, 20, to break open the relevantseal(s) enough so that the lid, 20, is completely open, as seen inFIG. 1. Thus, the peak first opening strength, would be measured, forexample, after a consumer purchases a package containing a granulardetergent, and in preparation to use the granular detergent containedtherein. After the peak first opening strength is achieved, and thepackage seal(s) start to break, the force required to progress to acompletely open package typically decreases significantly. The half-cut,38, herein is a cut in the paperboard which does not completely slicethrough the paperboard. Instead, it cuts through only a portion of thepaperboard. Thus, when force is exerted on the paperboard, thepaperboard itself separates between the interior and exterior surfacesof the paperboard. Such a half-cut seal therefore typically breaks openwith significantly less force than, for example, a traditional gluedseal which requires that the glue be pealed off of at least one surfacein order to break the seal. The half-cut, 38, may be employed inconjunction with a full-cut, 39, to adjust the peak first openingstrength of the package. The full-cut may also, of course, furtherdefine an opening tab, 37, a lock tab, 28 a, a locking mechanism, 28,etc. The full-cut, 39, herein is a “normal” cut which slices completelythrough the paperboard.

[0026] Accordingly, it is preferred that the package have a peak firstopening strength of less than about 70 N, preferably from about 3 N toabout 60 N, and more preferably from about 5 N to about 40 N, asmeasured perpendicular to the lid prior to opening. Additional seals,and methods of assembling blanks into packages are described in, forexample, WO 00/51897 to Hofte, published on Sep. 8, 2000.

[0027]FIG. 4 shows a preferred locking mechanism, 28, as seen from anenlarged partial cross-sectional side view of the package of FIG. 2,taken along line 4-4. In FIG. 4, the lock tab, 28 a, is seen engagedwith lock slot, 28 b. An adhesive portion, 40, affixes the first panelto a first panel flap, 42, which are formed by a fold, 44. In thefigures, fold lines are indicated by dashed lines. In FIG. 4, the angle,θ, indicates the angle between the lid front panel, 26, and the locktab, 28 a, when the lid, 20, is closed. This angle is typically fromabout 5° to about 85°, preferably from about 20° to about 80°, and morepreferably from about 30° to about 70°. Without intending to be limitedby theory, it is believe that this angle also increases the soundpressure level of the auditory locking sound, by enhancing the locking“click” of the package when the lid is closed.

[0028] As can also be seen in FIG. 4, there exists a gap, A, between theinner surface of the lid front panel, 26, and the exterior surface ofthe first panel, 14, which enhances the audible locking sound made whenthe lid, 20, is closed and the lock tab, 28 a, locks into the lock slot,28 b. For purposes of clarity, it is reiterated that this gap, A,corresponds to the difference in depth between α and β, described above.Furthermore, in FIG. 4 it can be seen that the lock slot, 28 b, has adepth, B, which is preferably from about 0.2 mm to about 5 mm,preferably from about 0.5 mm to about 3.5 mm, and more preferably fromabout 0.7 mm to about 2 mm, for use with a lock tab formed from apaperboard having a thickness of about 0.7 mm to 1 mm. For packageswhere the lock tab is formed from a thicker paperboard, this lock slotdepth, B, may be correspondingly larger. Such a depth helps to ensurethat the locking mechanism stays locked and that the lock tab, 28 a,seldom unintentionally slips out of the lock slot, 28 b.

[0029] In FIG. 5, an enlarged partial cross-sectional side view of apreferred embodiment of an alternate locking mechanism is provided whichis formed by a double layer of paperboard forming the lid front panel,26, and the lock tab, 28 a. The lock tab, 28 a, engages a lock shelf, 28c, to form the locking mechanism, 28. The lock shelf, 28 c, is az-folded section, 46, formed by two folds, 44, at the top of the firstpanel flap, 42, proximate to the double layered lid, 20. A half-cut, 38,allows the double layer of the lock tab, 28 a, to be more easily formedin the first panel, 14, and also provides a sharper edge which in turnforms a more secure locking mechanism, 28.

[0030] Multiple adhesive portions, 40, affix the double layered locktab, 28, to itself; affix the z-folded section, 46 to itself; and thedouble layered lid, 20, to itself. In addition, an adhesive portion, 40a, affixes the top of the first panel, 14, to the interior layer of thelid, 20. A half-cut, 38, positions exterior to the adhesive portion, 40a, allows a user to open the package by lifting the lid, 20, andseparating the inner paperboard layer of the lid, as the strength of thepaperboard is significantly less than the strength of the adhesiveportion affixed to the interior lid, 20, and the top of the first panel,14. Multiple half-cuts of varying depths are also useful herein, as ahalf-cut need not necessarily go exactly half way through thepaperboard. Furthermore, the depth of the half-cut may be coordinatedwith various properties of the internal layers of the paperboard(orientation of fibers, laminates, tear strength, etc.), so as toprovide the desired peak first opening strength.

[0031] In FIG. 6, a top plan view of a preferred blank, 36, suitable formaking the reclosable paperboard package herein, with a close-up of apreferred opening tab, 37, is provided. The package, 10, is preferablyformed by folding the blank along the plurality of folds, 44, andhalf-cuts, 38 and 38 a, and affixing an adhesive portion (not shown) ina plurality of locations understood by one skilled in the art. Theopening tab, 37, is affixed to the inside lid, 20, preferably with anadhesive portion (not shown), and breaks away during the first openingof the package, 10, as do certain portions which are designated bycorresponding half-cuts, 38 and 38 a. Thus, half-cuts, 38 and 38 a, maybe used to either provide breakaway seals, or may be used to promotedesired folding, such as for lock tab, 28 a. The outer edge of the locktab, 28 a, is straight and therefore provides a larger locking surfacethan, for example, that of FIG. 3.. Accordingly, the audible lockingsound may be greater.

[0032]FIG. 6 also shows a preferred gripping tab, 48, which provides theconsumer with something to more easily grip and pull during any time thelid, 20, is to be lifted. Also present in FIG. 6, are corner tabs, 50,which are folded into the lid to provide structural strength to thecorner if the lid, 20. The corner tabs, 50, also serve to provide asmooth and comfortable edge for those consumers who prefer to open thepackage from the corner, rather than the gripping tab, 48. This may beespecially important during the first opening of the package, when thefirst opening strength is greatest.

[0033] Side glue tabs, 52, in FIG. 6 are shortened by a distance, ε, ascompared to the depth, β, of the lid, 20. During formation of thecontainer, glue or similar adhesive (not shown) is applied to the sideglue tabs, 52, which are then affixed to the side panels, 18. Thedistance, ε, increases the flexibility of the lid, 20, and also reducesthe peak first opening strength. However, if the distance, ε, is toolarge, then the peak opening strength may be too small, and thereforethe container may accidentally open during shipping or transport. Thus,if present, the distance, ε, is typically from about 10% to about 45% ofthe depth, β, preferably from about 20% to about 35% of the depth, β,and more preferably from about 25% to about 30% of the depth, β.

[0034] As noted above, the paperboard package is formed of a singlepiece of paperboard, which significantly reduces manufacturingcomplexity and raw material costs. The paperboard useful herein istypically from about 0.3 mm to about 4 mm, preferably from about 0.5 mmto about 2 mm in thickness, and has a stiffness of from about 5 (mN)*(m)to about 80 (mN)*(m), preferably from about 15 (mN)*(m) to about 60(mN)*(m), and more preferably from about 20 (mN)*(m) to about 55(mN)*(m) in the cross-machine direction, and a stiffness in the machinedirection of from about 35 (mN)*(m) to about 120 (mN)*(m), preferablyfrom about 50 (mN)*(m) to about 108 (mN)*(m), and more preferably fromabout 58 (mN)*(m) to about 100 (mN)*(m). It has now been surprisinglyfound that the stiffness of the paperboard, in combination with theangle, θ, between the front panel and the lid, significantly contributesto the level of the audible locking sound, as well as the user'simpression of how secure the lid is locked.

[0035] The paperboard useful herein may contain a single, or multiplelayers of paper, laminate, reinforcing materials, moisture barriermaterials, etc. Each layer may be independently oriented, random,unoriented, etc. as desired.

[0036] The package, 10, preferably is used to store a granular material,30, and especially a granular detergent composition, such as that usedto wash laundry. Examples of preferred granular detergents useful hereininclude those described in, U.S. Pat. No. 5,496,487 to Capeci, et al.,issued on Mar. 5, 1996; U.S. Pat. No. 4,963,226 to Chamberlain, issuedon Oct. 16, 1990; and U.S. Pat. No. 4,129,511 to Ogoshi, et al., issuedon Dec. 12, 1978. In addition, the package, 10, can be used to store anyother products where it is desired to provide a freshness seal and/orprevent exposure of the product to the air or moisture, or whererepeated opening and closing is desired. While the present invention isdescribed herein with reference to the exemplary six-sided package ofFIG. 1, it is contemplated that the present invention can be adapted foruse with other package configurations and shapes. For example, thepresent invention can be used with packages having one or more curved orcurvilinear panels and the like. Further, the present invention can beused with top fill and side fill cartons. While the package, 10, isillustrated in FIG. 1 with the lid, 20, disposed at the top of thecarton, it is contemplated that the lid, 20, can be placed at otherlocations, and other lid configurations can be accommodated.

[0037] Sound Pressure Level

[0038] Sound Pressure Level (SPL) is a single measurement of soundpressure in decibels relative to the threshold of hearing which isdefined herein as 2×10⁻⁵ Newtons per Meter² or 20 microPascals. When SPLmeasurements are made, some adjustment for the ear's response to lowfrequency is usually included. This is done by using filters that followthe Fletcher-Munson curves—the A curve follows F&M at low levels and theB curve follows intermediate levels. The C curve is nearly flat.

[0039] The Fletcher-Munson curves turn down because the loudness curveindicates sensitivity. When a low level and low frequency noise occurs,it is difficult to hear, and thus is not weighted as much as amid-frequency noise at the same level. SPL is usually measured withspecial meters that have the weighting curves built in. The A curve isused for soft measurements and the C curve is used for loud sounds.However, for comparative measurements like transmission loss, the “flat”curve is used. The SPL measurement thus has the units of dB_(SPL).

[0040] The audible locking sound, as defined herein, is measured in aquiet room (background noise level 64-65 dB_(SPL) by a model OS-556Testo Term sound meter, set to a flat curve. The package to be measuredis placed 1 cm from the microphone with the lid opened. The lid is thenclosed by hand at a normal closing speed, and then the sound pressurelevel measured and recorded. This is repeated three times, and anaverage sound pressure level is calculated.

[0041] The audible locking sound useful herein has a sound pressurelevel of at least about 78 dB_(SPL), preferably from about 80 dB_(SPL)to about 100 dB_(SPL), and more preferably from about 81 dB_(SPL) toabout 88 dB_(SPL). Typical paperboard cartons lacking the lockingmechanism described herein and/or formed of paperboard not having thestiffness described above typically have a sound pressure level of fromabout 66 dB_(SPL) to 76 dB_(SPL).

EXAMPLE 1

[0042] A reclosable paperboard package is formed according to FIG. 3,and has an audible locking sound resembling a “double-click”, and asound pressure level of 81.7. When in the closed position after the peakfirst opening, the lid and the first panel are separated by a distanceof 4.5 mm. The paperboard has a stiffness of in the machine direction offrom 94-102 (mN)*(m) and a stiffness in the cross-machine direction offrom 34-37 (mN)*(m), and is about 0.7 mm thick. This package has a peakfirst opening strength of about 40 N. The paperboard is a sandwich boardwith a 40 μm polyethylene lamination layer.

EXAMPLE 2

[0043] A reclosable paperboard package is formed according to FIG. 1,except that only two locking mechanisms are present. The package has anaudible locking sound resembling a “double-click”, and a sound pressurelevel of 82.3. When in the closed position after the peak first opening,the lid and the first panel are separated by a distance of at 1.4 mm.The paperboard has a stiffness in the machine direction of from 95-98(mN)*(m) and a stiffness in the cross-machine direction of from 36-37(mN)*(m). The paperboard is about 0.7 mm thick. This package has a peakfirst opening strength of about 40 N. The paperboard is a sandwich boardwith a 40 μm polyethylene lamination layer.

EXAMPLE 3

[0044] A recloseable paperboard package is formed according to FIG. 6,except that only two locking mechanisms are present. The package has anaudible locking sound resembling a “double-click”, and a sound pressurelevel of 82. When in the closed position after the peak first opening,the lid and the first panel are separated by a distance of at 1.4 mm.The paperboard has a stiffness in the machine direction of from 95-98(mN)*(m) and a stiffness in the cross-machine direction of from 36-37(mN)*(m). The paperboard is about 0.7 mm thick, and distance, ε, =27% ofthe depth, β. This package has a peak first opening strength of about 22N, due to the distance, ε, and the gripping tab. The paperboard is asandwich board with a 40 μm polyethylene lamination layer.

[0045] While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A reclosable paperboard package for containing agranular material comprising: A. a container base comprising a firstpanel; and B. a lid attached to the container base by a folded hinge,wherein the container base and the lid are formed of a single piece ofpaperboard, wherein the lid and the first panel form a lockingmechanism, and wherein when the closing of the lid creates an audiblelocking sound having a sound pressure level of at least about 78dB_(SPL).
 2. The reclosable paperboard package of claim 1, wherein thelocking sound has a sound pressure level of from about 80 dB_(SPL) toabout 100 dB_(SPL).
 3. The reclosable paperboard package of claim 1,wherein the lid has a peak first opening strength of less than about 70N.
 4. The reclosable paperboard package of claim 1, wherein when in theclosed position after the peak first opening, the lid and the firstpanel are separated by a distance of from about 0.5 mm to about 15 mm.5. The reclosable paperboard package of claim 1, wherein the paperboardhas a stiffness of from about 5 (mN)*(m) to about 80 (mN)*(m) in thecross-machine direction and a stiffness of from about 35 (mN)*(m) toabout 120 (mN)*(m) in the machine direction.
 6. The reclosablepaperboard package of claim 1, wherein the lid and the first panel format least 2 locking mechanisms.
 7. The reclosable paperboard package ofclaim 1, wherein the locking mechanism is distal from the folded hinge.8. The reclosable paperboard package of claim 1, further comprising agranular detergent composition therein.
 9. The reclosable paperboardpackage of claim 3, further comprising a half-cut seal between the lidand the first panel.
 10. A reclosable paperboard package for containinga granular material comprising: A. a container base comprising a firstpanel and a second panel distal to the first panel; and B. a lidattached to the second panel by a folded hinge, and a half-cut sealattaching the lid to the first panel, wherein the container base and thelid are formed of a single piece of paperboard having a stiffness offrom about 5 (mN)*(m) to about 80 (mN)*(m) in the cross-machinedirection and a stiffness of from about 35 (mN)*(m) to about 120(mN)*(m) in the machine direction, wherein the lid and the first panelform a locking mechanism, wherein the lid has a peak first openingstrength of less than about 70 N, wherein when in the closed positionafter the peak first opening, the lid and the first panel are separatedby a distance of from about 0.5 mm to about 15 mm, and wherein when theclosing of the lid creates an audible locking sound having a soundpressure level of at least about 78 dB_(SPL).